* ext/psych/lib/psych/visitors/to_ruby.rb: quoted "<<" strings
  should not be treated as merge keys.
* ext/psych/lib/psych/visitors/yaml_tree.rb: hashes with keys
  containing "<<" should roundtrip.
* test/psych/test_merge_keys.rb: test for change. Fixes GH #203

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47315 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-08-30

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47316 b2dd03c8-39d4-4d8f-98ff-823fe69b080e